What should you know about red eye aafp?

Red eye is often caused by irritation, dryness, allergy or conjunctivitis, but pain, vision changes, injury or light sensitivity need prompt medical assessment. The colour change usually comes from widened or irritated small blood vessels on the surface of the eye. One or both eyes may be affected, and discharge, watering, itching or a gritty feeling can help point towards the cause.

A red eye may follow smoke, dust, swimming-pool chemicals, prolonged screen use or rubbing. Dryness can make the eye feel scratchy or burning. Itching in both eyes with watery discharge can occur with allergic conjunctivitis; see the guide to [Allergic Conjunctivitis](/conditions/allergic-conjunctivitis/). Pink or red tissue with sticky discharge, irritation and spread between people can occur with conjunctivitis; read more about [Conjunctivitis](/conditions/conjunctivitis/). A small patch of bright red on the white of the eye can result from a surface blood vessel leaking and may look dramatic even when discomfort is limited. A clinician should assess a red eye when the pattern does not fit simple irritation or is getting worse.

Do not rub the eye. Rinse away a suspected irritant with clean, lukewarm water, and remove contact lenses. Use a cool clean compress for itching or puffiness, and take breaks from screens if they worsen discomfort. Wash your hands before and after touching your face; do not share towels, eye makeup or pillowcases if discharge is present. Avoid wearing contact lenses until the eye feels normal and a professional advises that it is safe. Do not use leftover prescription drops, particularly drops intended to reduce redness, because the wrong product can mask symptoms or irritate the eye further. A pharmacist or clinician can help choose suitable lubricating drops when dryness is the likely cause.

Seek urgent medical care for severe eye pain, a sudden change or loss of vision, marked sensitivity to light, a severe headache with nausea, a cloudy-looking cornea, or an eye that is difficult to open. Get prompt assessment after an eye injury, chemical splash or suspected foreign body; flush a chemical exposure with clean water while arranging help. Contact-lens wearers should seek same-day advice for a painful or very red eye, because infection can affect the cornea. Arrange a medical review if symptoms persist, recur without a clear trigger, or come with thick discharge, swelling around the eye or fever.

You could ask: What is the likely cause of the redness? Does the surface of my eye need testing? Should I stop contact lenses or any eye products? Which symptoms would mean I need urgent review? If discharge is present, how can I reduce the chance of passing it to someone else?